Housings of the type, mentioned in the introduction, for an electrical device, which may be, for example, an emergency stop device of a dangerous machine or a technical system, are known from the prior art in a variety of embodiments. In particular, in the case of housings for emergency stop devices, it is known, for example, to screw the housings tightly to a base or a retainer after previously opening the housing with its housing bottom. In order to make the assembly particularly easy, there exist electrical devices that can already be completely wired by the manufacturer and then during assembly can be fastened without tools to a retainer, which has been pre-configured for this purpose and provided on the machine or alternatively the technical system, in particular, can be snapped onto a retaining element of the retainer. Such housings have the drawback that the fastening element, with which the housing is interlocked with the retaining element, is accessible from the outside. Therefore, after installation, these electrical devices can be easily deinstalled again with little effort and then optionally reinstalled such that this reinstallation would not be detectable later on. An unauthorized deinstallation and reinstallation of electrical devices can present a problem, in particular, in the case of safety-critical machines or technical systems.
The published document DE 195 04 762 C2 discloses a device to snap a housing of an electrical device onto a mounting rail profile. The unlocking mechanism consists of a pull rod, which can be mounted laterally or inside the housing. By pulling on the pull rod, a spreader bar is moved into its operating position on the underside of the housing, and the housing can be removed from the mounting rail.
The published document DE 10 2015 201 916 A1 discloses a housing of an electrical device that can be snapped onto a top-hat rail. The locking of the housing to the retainer takes place via an eccentric element on the rear side of the housing. In this case the eccentric element is rotatably actuated from the front side of the housing by a torsion bar and a control element. The housing can be disassembled together with the locking apparatus.
In the case of the two solutions mentioned above, there is no way to detect an unauthorized disassembly of the housing from the retainer. Furthermore, these housings have corresponding openings, through which the tension rod or alternatively the torsion bar is passed. As a result, it is not possible or only with considerable effort is it possible to provide a housing with a greater level of protection, in particular, with the IP65 level of protection.